Experimental investigation and optimization of friction stir welding parameters to manufacture AA6061-B4C composite material using design of experiments

Abstract

This study presents an experimental investigation into the friction stir welding (FSW) of AA6061 aluminum alloy reinforced with 10 wt% boron carbide (B4C) particles, aiming to optimize process parameters for enhanced mechanical performance. A square tool profile was introduced and compared with cylindrical tapered and cylindrical full-threaded profiles to assess its influence on weld quality. Using the Taguchi method with an L27 orthogonal array, the effects of tool rotational speed (700, 1000, 1400 rpm), welding speed (40, 50, 63 mm/min), and tool profile were systematically examined with respect to the ultimate tensile strength (UTS) of the welded joints. The results revealed that tool rotational speed (N) had the most significant influence on UTS, followed by welding speed (S) and tool profile (P). The optimal combination of 700 rpm rotational speed, 40 mm/min welding speed, and square tool profile (N1S1P2) achieved a Maximum ultimate tensile UTS of 126.88 MPa. Statistical validation using analysis of variance (ANOVA) and signal-to-noise (S/N) ratio analysis confirmed the significance of the selected parameters. Furthermore, microstructural and fractographic analyses demonstrated a uniform dispersion of B4C particles and enhanced load-bearing characteristics. This study highlights the effectiveness of using B4C reinforcement and square tool geometry in improving FSW joint strength, offering valuable insights for advanced composite welding applications.